In various industrial fields, an extruder extruding a highly-viscous substance is used. Generally, the extruder is loaded with a highly-viscous substance in an extruder main body and extrudes the highly-viscous substance in the extruder main body with a pressing tool from a nozzle of the extruder main body, and the extruded highly-viscous substance is incorporated in an incorporating object. For example, Patent Document 1 (FIG. 2) discloses details of loading metallic sodium into an extruder main body and extruding the metallic sodium with a pressing tool from a nozzle of the extruder main body to the outside so as to fill metallic sodium, i.e., a highly-viscous substance, as a cooling medium into a hollow engine valve used as an incorporating object.
The extruders are recently increasingly automated and, when it is detected that a highly-viscous substance is extruded from an extruder (extruder main body) to a predetermined position, the movement of the pressing tool in the extruder is stopped and the extruded highly-viscous substance is cut by a cutting tool. As a result, a highly-viscous substance to be incorporated into one incorporating object is easily acquired.